The present invention pertains to a process and system for the automatic stacking, storage and removal of packaged merchandise from large warehouse installations of the type wherein the handling of the merchandise is controlled by a computer. In particular, the invention relates to a process system wherein the merchandise is withdrawn sequentially from several shelves provided with product magazines and loaded into passing transport containers.
Increasing demand is being made upon wholesale suppliers due to the growing variety of product lines being offered on the market in Western industrialized countries. For example, pharmacists are supplied by wholesalers who often have to deliver several thousand articles of different types within the shortest possible time.
Presently, most large-scale warehouse operations are conducted manually. More particularly, each warehouse clerk removes the required number of merchandise items indicated on an order slip from the particular section of product magazines for which he is responsible, whereupon the items are loaded into a transport container located next to the clerk. The transport container moves from one warehouse clerk to the next where it is again stopped for loading. This mode of warehousing or merchandise withdrawal results, on the one hand, in a high cost factor and, on the other hand, necessitates a great degree of labor. Even more importantly from the viewpoint of the wholesaler than the cost factor is the speed with which an order is filled. Thus, it is a well known fact, particularly in the pharmaceutical industry, that wholesalers differ from each other essentially only in the length of delivery times required.
For the above reasons, processes and systems for the automatic withdrawal of packaged merchandise from large warehouses have recently been proposed.
A system for storing packaged merchandise in horizontal magazines is disclosed in U.S. Pat. No. 3,881,633. In order to remove the merchandise from the magazines, a plunger, which is movable along the entire length of the magazine by a chain drive, pushes the stack of merchandise items in a manner such that the forwardmost ones of the items fall over the forward edge of the magazine onto a conveyor belt running beneath the magazines. However, on the one hand, this device is exceedingly difficult to load and, on the other hand, it is relatively expensive due to the particular design of the plunger. Furthermore, the merchandise items forming a part of a particular order are situated on the conveyor belt along with other items unless special steps (not indicated in the references patent) are taken to prevent this from happening.
In another design disclosed in the above-identified patent, a separate gripping device is disclosed which moves along the row of magazines to extend into the magazines to eject a number of pieces, determined by a computer, over the forward edge of the magazine onto a conveyor. The conveyor then delivers the batch of items belonging to a single order to transport containers which are successively directed to the conveyor. However, even in such an arrangement, it is extremely difficult and time-consuming to separate the items of one batch arriving on the container from items of other batches and to load these items separately into the various transport containers.
Additionally, it is not possible even with these two automatically operating mechanisms to withdraw items while the magazines are being filled. As a result, at least a portion of the mechanism must be shut down when individual magazines are being filled, such shut-down naturally disrupting the operation of the entire system unless the withdrawal of the items over the entire system is temporarily halted. On the other hand, since it is not possible to design the magazines to be sufficiently large to contain the requirements of an entire day (too many packages would be squeezed against each other during withdrawal), the withdrawal of merchandise will be unavoidably delayed several times during the course of the day. Thus, the operation of the entire installation must be halted if even only a single magazine must be restocked.